Liquid crystal displays continue to be a dominant technology for flat panel displays. Liquid crystal displays that do not use polarizers, are reflective, and have intrinsic display memory are desirable in many situations. A number of reflective cholesteric liquid crystal displays has recently been developed. But these conventional reflective cholesteric liquid crystal displays typically suffer from one or more of the following deficiencies: switching between two states (e.g., planar state and focal-conic state) where one or both states are not stable under zero electric field; difficulty in fabricating black and white displays since one of the states must be colored (i.e., a color other than white or black); viewing angle dependency; poor light reflectivity; and poor contrast between the two states. There is a need, addressed by the present invention, to minimize or avoid one or more of above described problems.
The following documents may be relevant to the present invention:
Yang et al., U.S. Pat. No. 6,061,107.
Tamaoki et al., U.S. Pat. No. 6,103,431.
Yang et al., U.S. Pat. No. 5,847,798.
Doane et al., U.S. Pat. No. 5,691,795.
Wu et al., U.S. Pat. No. 5,625,477.
Wu et al., U.S. Pat. No. 5,661,533.
D. K. Yang et al., “Polymer-stabilized Cholesteric Textures,” Liquid Crystals in Complex Geometries Formed by polymer and porous networks, pp. 103–142 (Published by Taylor & Francis Ltd. 1996).                H. Yuan, “Bistable Reflective Cholesteric Displays,” Liquid Crystals in Complex Geometries Formed by polymer and porous networks, pp. 265–280 (Published by Taylor & Francis Ltd. 1996).        J. Kim et al., “White Reflective Displays from Polymer-Stabilized Cholesteric Textures,” SID, p. 802–805 (1998).        D.-K. Yang et al., “Cholesteric liquid crystal/polymer dispersion for haze-free light shutters,” Appl. Phys. Lett., Vol. 60, pp. 3102–3104 (June 1992).        J. Nie et al., “Photocuring of mono- and di-functional (meth)acrylates with tris [2-(acryloyloxy)ethyl]isocyanurate,” European Polymer Journal, Vol. 35, pp. 1491–1500 (1999).        
W. D. Cook, “Photopolymerization kinetics of dimethacrylates using the camphorquinone/amine initiator system,” Polymer, Vol. 33, pp. 600–609 (1992).
I. Dierking, “Polymer Network-Stabilized Liquid Crystals,” Adv. Mater., Vol. 12, pp. 167–181 (2000).
D.-K. Yang et al., “Control of reflectivity and bistability in displays using cholesteric liquid crystals,” J. Appl. Phys., Vol. 76, pp. 1331–1333 (1994).
E. Korenic et al., “Cholesteric Liquid Crystal Flakes—A New Form of Domain,” LLE Review, Vol. 74, pp. 139–149 (1998).
N. Tamaoki et al., “Rewritable Full-Color Recording in a Photon Mode,” Adv. Mater., Vol. 12, pp. 94–97 (2000).
W. Schuddeboom et al., “Excited-State Dipole Moments of Dual Fluorescent 4-(Dialkylamino)benzonitriles. Influence of Alkyl Chain Length and Effective Solvent Polarity,” J. Phys. Chem., Vol. 96, pp. 10809–10819 (1992). The compound of formula 1-I described in the present application is disclosed in Schuddeboom et al.